code: def call(self, attr_name, value):
      if len(value) != self.k:
          raise ValueError(
              f"{attr_name} must have exactly {self.k} elements (got {len(value)!r}, elems: {value!r})"
          )
  
imports: from abc import ABC, abstractmethod
  from typing import TypeVar, Union
label_desc: Use image node_id 2 for calling the Length obj's underlying member method code with example usage: obj.call(attr_name, value) without return types